Driven layon roller apparatus for film or sheet winders

ABSTRACT

A driven layon roller apparatus for a plastic film or sheet winder is driven in rotation by a magnetic coupling. The magnetic coupling allows for torque to be transmitted to the layon roller of the apparatus to rotate the layon roller while adding little or no inertia and imposing little or no radial force to the layon roller as the layon roller moves position relative to the winder.

BACKGROUND

The present invention pertains to a layon roller for a plastic film or sheet winder. The layon roller is driven in rotation by a coupling to a drive source where the coupling enables the layon roller to float on the roll of film or sheet wound on the winder and maintain a very precise and accurate pressure on the roll.

DESCRIPTION OF THE RELATED ART

One critical process when producing film products such as a plastic film or sheet is the ability to be able to wind the final product plastic film or sheet into rolls. The process of winding plastic film or sheet into rolls is done in a machine called a winder. There are many different types of winders, and they all use specific characteristics to achieve different properties in the rolls of film or sheet wound on the winders.

A basic type of plastic film or sheet winder is a center winder such as that represented schematically in FIG. 1. In a center winder of the type shown in FIG. 1 the shaft of the winder is driven in rotation and a torque produced by the winder rotation is transmitted through the roll of film or sheet wound on the winder to the surface of the roll. The torque exerts a pulling force on the film or sheet being gathered onto the roll. In a center winder such as that shown in FIG. 1, either the torque of the winder shaft or the speed of the winder shaft or a combination of both is varied to adjust the tensile force in the film or sheet being wound on the winder and maintain the tensile force in the film or sheet substantially constant.

In order to control variables of the film or sheet being wound on the roll on the winder, for example air entrapment between the film or sheet and the exterior of the roll, a second idle roller known as a layon roller is positioned against the roll on the winder where the film or sheet is being wound onto the roll. The layon roller applies a force on the roll wound on the winder. This is represented in FIG. 2. The applied force of the layon roller on the roll wound on the winder is commonly generated by pneumatic pressure, but other electrical devices and mechanical or hydraulic devices can be used to cause the layon roller to apply a force on the roll being wound on the winder.

When designing layon rollers that are used with film or sheet winders such as that represented in FIG. 2, it is crucial that the layon roller have the ability to maintain very precise and accurate pressure that is applied by the layon roller to the exterior surface of the roll of film or sheet being wound on the winder. To accomplish this precise and accurate control of the pressure applied by the layon roller, a “floating” type layon roller is often used with a film or sheet winder. A “floating” type layon roller has very low inertia and friction, and employs a torque tube or similar device to maintain axial alignment of the layon roller torque tube axis of rotation with the axis of rotation of the winder. The layon roller is free to ride on the surface of the roll being wound on the winder as the roll grows in diameter or circumference, and thereby the layon roller maintains a substantially constant applied force to the surface of the roll being wound on the winder.

In order to maintain tension in the plastic film or sheet being pulled toward the winder as the film or sheet accumulates on the roll being wound on the winder, the torque required to rotate the center shaft of the winder increases due to the effective diameter increase of the roll on the winder. However, the increased torque required to rotate the roll being accumulated on the winder is transmitted through the accumulated layers of the film or sheet wound on the winder and is inherently detrimental to the final roll characteristics.

SUMMARY

To have better control of the tension in the film or sheet being wound on the roll on the winder it is necessary to remove the variable torque being transmitted through the roll on the winder. Another torque transmission with a constant force distance relative to the roll wound on the winder must be provided. This can be done by adding torque to the layon roller. This is known as center surface winding and it is represented in FIG. 3.

Although applying a torque to the layon roller is a straight forward concept, the process of adding a power transmission to apply torque to the layon roller has a major side effect. Adding a drive transmission to the layon roller to supply torque to the layon roller removes the ability of the layon roller to still be able to float freely on the surface of the roll being wound on the winder. This in turn removes the ability of the layon roller to maintain a very delicate and precise pressure against the film or sheet roll being wound on the winder.

The present invention overcomes this problem by providing a layon roller having a coupling to a source of rotation where the coupling makes use of a magnetic flux field to transmit rotation to the layon roller. The coupling is basically comprised of first and second magnets that are adjacent, but not physically connected. Rotation of the first magnet causes rotation of the second magnet through the magnetic flux field. In this way the coupling enables the layon roller to transmit torque to the roll being wound on the winder while still being able to float on the roll and maintain a very precise and accurate pressure on the roll.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the invention are set forth in the following detailed description of the invention and in the drawing figures.

FIG. 1 is a schematic representation of a plastic film or sheet center winder.

FIG. 2 is a schematic representation of a plastic film or sheet center winder with a layon roller.

FIG. 3 is a schematic representation of a plastic film or sheet center winder with a layon roller where torque is being applied to the layon roller.

FIG. 4 is a partial perspective view of one advantageous embodiment of the driven layon roller for a film or sheet winder of the invention.

FIG. 5 is a partial elevation view of the layon roller of FIG. 4.

DESCRIPTION

FIG. 4 shows the driven layon roller for a film or sheet winder of the invention 10. The driven layon roller of FIG. 4 isolates forces associated with transmitting rotation power or torque to the layon roller and thereby maintains the ability of the layon roller to provide very delicate and precise pressure against the roll wound on the winder.

The driven layon roller of the invention shown in FIG. 4 has a unique coupling that allows for torque to be transmitted to the layon roller to rotate the layon roller while adding little or no inertia and imposing little or no radial forces to the layon roller as the layon roller moves position relative to the winder.

The unique coupling of the invention 10 shown in FIG. 4 is a magnetic coupling. The magnetic coupling uses magnetic forces to transmit torque to the layon roller, but still allows for axial and parallel misalignment, with minimal effect on the delicate and precise pressure exerted by the layon roller on the roll of film or sheet wound on the winder.

Referring to FIGS. 4 and 5, the driven layon roller apparatus 10 of the invention includes a supporting frame 12, as is conventional. In FIGS. 4 and 5 only the right hand side of the frame is shown. In the illustrative embodiment shown, the coupling of the invention is located at the right side of the frame. However, it could also be located at the left side. A cylindrical stub shaft 14 projects from the side of the frame 12 into the frame interior. The cylindrical stub shaft 14 surrounds an opening 16 through the side of the frame 12. A pair of bearing assemblies 18 are mounted on the exterior surface of the stub shaft 14. A generally cylindrical drive hub 20 is mounted on the pair of bearing assemblies 18 and rotates on the stub shaft 14.

A transmission drive assembly rotates the drive hub 20 on the stub shaft 14. In the embodiment of the apparatus shown in FIGS. 4 and 5, the drive transmission is comprised of a driven sprocket 22 secured on the drive hub 20, a drive sprocket 24 and a chain 26 looped around the driven sprocket 22 and the drive sprocket 24. Although a sprocket and chain drive transmission is shown in FIGS. 4 and 5, other equivalent types of drive transmissions can be employed in the apparatus to selectively rotate the drive hub 20 on the stub shaft 14.

A central shaft 28 is supported on the frame 12. Although only the right hand end of the shaft 28 is shown in FIGS. 4 and 5, the left hand end of the shaft is supported by the frame 12 in a similar manner to that of the right-hand end of the shaft to be described. The shaft right hand end 30 extends into a pivoting shaft support 32 that in turn is mounted in the opening 16 of the frame 12. The shaft end 30 is mounted in a cylindrical portion 32 of the pivoting shaft support. As shown in FIGS. 4 and 5, the cylindrical portion 32 of the shaft support is slightly smaller than the frame opening 16. A flange portion 34 of the pivoting shaft support extends radially outwardly from the cylindrical portion 32. A pivot pin 36 connects the flange portion 34 to the frame 12 and enables the pivoting shaft support to pivot in the frame opening 16 relative to the frame.

A pivot actuator 38 is connected between the frame 12 and the flange portion 34 of the shaft support. Selective extension and retraction of the pivot actuator 38 causes the flange portion 34 of the shaft support to pivot about the pivot pin 36, and thereby causes the central shaft 28 to move in a pivoting movement relative to the frame 12. The pivoting movement of the central shaft 28 selectively moves the shaft away from and toward a roll of film 40 wound on a shaft positioned adjacent the apparatus of the invention.

A bearing assembly 42 is mounted on the central shaft 28 adjacent its right hand end 30. A similar bearing assembly is mounted on the shaft 28 adjacent the left hand end of the shaft. A pair of support discs 44 are mounted on the bearing assemblies 42. The bearing assemblies 42 enable the support discs 44 to rotate freely on the central shaft 28.

The pair of support discs 44 support the cylindrical layon roller 46 for rotation of the roller on the central shaft 28. The layon roller 46 has a cylindrical exterior surface 48 and an opposite cylindrical interior surface 50 that surrounds a hollow interior volume 52 of the roller. The layon roller 46 has an axis of rotation that is coaxial with the center axis 54 of the central shaft 28.

A driven hub is mounted to the support disc 44 adjacent the right hand end of the central shaft 28. The driven hub has an annular flange portion 56 that is secured to the support disc 44 to rotate with the support disc. The hub also has a cylindrical portion 58 that extends axially from the annular flange 56 and extends around the central shaft 28. The hub cylindrical portion 58 is spaced radially outwardly from the central shaft 28, whereby the driven hub is free to rotate around the central shaft.

As stated earlier, the driven layon roller apparatus has a unique coupling that allows for torque to be transmitted from the drive hub 20 to the layon roller 46 to rotate the layon roller while adding little or no inertia and imposing little or no radial force to the layon roller as the layon roller pivots relative to the roll of film 40. The unique coupling is a magnetic coupling. The magnetic coupling uses magnetic forces to transmit torque to the layon roller 46, but still allows for axial and parallel misalignment, with minimal effect on the delicate and precise pressure exerted by the layon roller 46 on the roll of film or sheet wound on the roll of film 40.

The magnetic coupling includes a magnetic first coupling piece 62. In the preferred embodiment the first coupling piece 62 is a permanent magnet. However, in other embodiments the first coupling piece 62 could be an electromagnet. The first coupling piece 62 has a general cylindrical configuration with a cylindrical exterior surface 64 that is secured inside the drive hub 20 for rotation of the first coupling piece 62 with the drive hub. The first coupling piece 62 also has a cylindrical interior surface 66 that surrounds and is spaced from the central shaft 28. Other configurations of the first coupling piece could be employed. The exterior 64 and interior 66 cylindrical surfaces have a center axis of rotation. The center axis of the first coupling piece 62 is parallel with the layon roller axis of rotation 54, but is not necessarily coaxial with the layon roller axis of rotation due to the ability of the layon roller to move in pivoting movements about the pivot pin 36. The first coupling piece 62 also has a flat annular surface 70 that faces toward the driven hub cylindrical portion 58.

The magnetic coupling also includes a magnetic second coupling piece 72. In the preferred embodiment the second coupling piece 72 is also a permanent magnet. The second coupling piece 72 is basically a mirror image of the first coupling piece 64. The second coupling piece 72 also has a cylindrical exterior surface 74 and an opposite cylindrical interior surface 76. Again, other configurations of the second coupling piece could be employed. The cylindrical interior surface 76 is secured to the driven hub cylindrical portion 58 whereby the second coupling piece 72 rotates with the driven hub, the support disc 44 secured to the driven hub, and the layon roller 46 mounted on the support discs. The second coupling disc 72 also includes a flat annular surface 80 that opposes and is parallel to the flat annular surface 70 of the first coupling piece 62.

The first coupling piece flat annular surface 70 and the second coupling piece flat annular surface 80 are parallel and axially spaced from each other with there being nothing but a void or empty space 82 between the two surfaces. However, the two surfaces 70, 80 are sufficiently close for the two magnets 62, 72 to produce magnetic flux that passes through the empty space 82 between the two magnets.

On rotation of the first coupling piece 62 by the driven sprocket 22, the magnetic flux in the empty space 82 between the first coupling piece annular surface 70 and the second coupling piece annular surface 80 imparts a rotation torque to the second coupling piece 72 which in turn is transmitted to the layon roller 46. However, because the first coupling piece 62 and the second coupling piece 72 are not physically connected and do not make physical contact, the layon roller 46 is free to float and pivot while simultaneously providing torque to the plastic film or sheet being wound on the roll of film 40. All forces associated with the power transmission from the driven sprocket 22 are isolated by the sprocket and the drive hub 20 that are mounted for rotation on the stub shaft 14 of the frame 12.

Although the drive transmission shown in FIGS. 4 and 5 is a sprocket and chain assembly, the concept of the invention would work equally well regardless of the initial power transmission. For example, the sprocket and chain assembly could be replaced with a pulley and belt drive or with a spur gear drive.

Another unique feature of the driven layon roller apparatus 10 of the invention is the positioning of the first magnetic coupling piece 62 and the second magnetic coupling piece 72 internally inside the hollow interior volume 52 of the layon roller 46. This provides a space saving option. Additionally, the first magnetic coupling piece 62 could be located outside the interior volume of the layon roller 46 with the second magnetic coupling piece 72 being positioned inside the hollow interior of the roller. Still further, both the first 62 and second 72 magnetic coupling pieces could be located outside the interior volume of the layon roller 46.

Although the layon roller of the invention has been described as being used with a plastic film or sheet winder, the layon roller would work equally well in other areas of substrate winding, for example winding a paper web, and the layon roller of the invention should not be interpreted as limited to use with only plastic film or sheet winders. Additionally, the magnetic couple could be used in other applications, for example on a surface winder.

As various modifications could be made in the constructions of the apparatus herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents. 

1. A driven layon roller apparatus for winders, the apparatus comprising: a frame; a central shaft supported on the frame; a layon roller mounted for rotation on the central shaft; a magnetic first coupling piece adjacent the layon roller, the first coupling piece being rotatable relative to the frame; and, a magnetic second coupling piece mounted stationary on the layon roller, the second coupling piece being adjacent the first coupling piece wherein magnetic flux between the first coupling piece and the second coupling piece causes the second coupling piece and the layon roller to rotate in response to rotation of the first coupling piece.
 2. The apparatus of claim 1, further comprising: the layon roller having an axis of rotation; and, the first coupling piece being rotatable around the layon roller axis of rotation.
 3. The apparatus of claim 1, further comprising: an empty space between the first coupling piece and the second coupling piece, the empty space preventing the first coupling piece and the second coupling piece from contacting.
 4. The apparatus of claim 1, further comprising: the first coupling piece having a flat surface; the second coupling piece having a flat surface; and, the first coupling piece flat surface and the second coupling piece flat surface being parallel and opposing each other.
 5. The apparatus of claim 4, further comprising: an empty space between the first coupling piece flat surface and the second coupling piece flat surface.
 6. The apparatus of claim 1, further comprising: the first coupling piece being a permanent magnet.
 7. The apparatus of claim 1, further comprising: the second coupling piece being a permanent magnet.
 8. The apparatus of claim 1, further comprising: a roll of film adjacent the layon roller.
 9. The apparatus of claim 8, further comprising: the layon roller being movable toward and away from the roll of film.
 10. The apparatus of claim 1, further comprising: the layon roller having a cylindrical exterior surface and a cylindrical interior surface, the cylindrical interior surface of the layon roller surrounding a hollow interior volume of the layon roller, and; the second coupling piece being inside the layon roller hollow interior volume.
 11. The apparatus of claim 10, further comprising: the first coupling piece being inside the layon roller hollow interior volume.
 12. The apparatus of claim 1, further comprising: a drive transmission operatively connected to the first coupling piece, the drive transmission being selectively operable to rotate the first coupling piece.
 13. A driven layon roller apparatus for winders, the apparatus comprising: a frame; a central shaft mounted on the frame and supported by the frame; a layon roller mounted for rotation on the central shaft, the layon roller having an axis of rotation that defines mutually perpendicular axial and radial directions relative to the layon roller; a magnetic first coupling piece mounted on the frame for rotation of the first coupling piece relative to the frame and around the layon roller axis of rotation; a drive transmission operatively connected to the first coupling piece for rotating the first coupling piece; and, a magnetic second coupling piece connected to the layon roller for rotation of the second coupling piece with the layon roller around the layon roller axis of rotation, the second coupling piece being adjacent the first coupling piece wherein magnetic flux between the first coupling piece and the second coupling piece causes the second coupling piece and the layon roller to rotate in response to rotation of the first coupling piece.
 14. The apparatus of claim 13, further comprising: the first coupling piece and the second coupling piece being separated axially by an empty space between the first coupling piece and the second coupling piece.
 15. The apparatus of claim 12, further comprising: the first coupling piece having a flat annular surface that extends around the layon roller axis of rotation; the second coupling piece having a flat annular surface that extends around the layon roller axis of rotation; and, the first coupling piece flat annular surface and the second coupling piece flat annular surface being parallel and axially spaced from each other.
 16. The apparatus of claim 15, further comprising: the first coupling piece flat annular surface and the second coupling piece flat annular surface being axially separated by an empty space.
 17. The apparatus of claim 13, further comprising: the first coupling piece and the second coupling piece being permanent magnets.
 18. The apparatus of claim 13, further comprising: a roll of film adjacent the layon roller.
 19. The apparatus claim 18, further comprising: the layon roller being movable toward and away from the roll of film.
 20. The apparatus of claim 13, further comprising: the layon roller having a cylindrical exterior surface and a cylindrical interior surface, the cylindrical interior surface surrounding a hollow interior volume of the layon roller; and, the second coupling piece being inside the layon roller hollow interior volume.
 21. The apparatus of claim 20, further comprising: the first coupling piece being inside the layon roller hollow interior volume. 